1. Field of the Invention
The present invention relates to a projection display apparatus which projects and displays an image on a screen.
2. Description of the Related Art
In recent years, liquid crystal projector apparatuses have been widely used as projection display apparatuses which project and display images. In an example of a liquid crystal projector apparatus, light is emitted from a light source and is modulated by a liquid crystal panel to form an optical image corresponding to an image signal. The thus-obtained optical image is magnified by a projector lens and is displayed on a screen.
A plurality of heat sources, such as the light source and electronic circuit components, are disposed in a housing of the liquid crystal projector apparatus. Therefore, the liquid crystal projector apparatus generally includes a cooling structure which exhausts air from the housing by using an axial fan disposed in the housing.
With regard to the cooling structure for the liquid crystal projector apparatus, various techniques have been proposed. For example, Japanese Unexamined Patent Application Publications Nos. 2005-242156 and 2005-25035 disclose a structure in which a louver which covers an exhaust side of the axial fan is provided with blade members having inclined portions so that an airflow resistance can be reduced and leakage of light from the housing can be reliably prevented. As another example, Japanese Unexamined Patent Application Publications No. 2005-10494 discloses a structure in which a louver is provided with exhaust-straightening walls which are arranged in a pattern of concentric circles or in a radial pattern with respect to the rotational center of the axial fan.